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Computer model experiment
I just completed a experiment with my antenna optimizer program where
I had a dipole in free space and where I increased the diameter until it was close to.003 ohms resistive What this means is the current flow is right at the surface where there is no skin depth penetration involved and thus close to zero material resistance. This means that the total resistance is the radiation resistance of the surface encapsulating particles. The radiation was 35 db in a shape close to that of a sphere. (when the resistance of the aluminum dipole went to zero the radiation went to a perfect sphere) Efficiency was stated at 100% efficient pointing to 100% accountability for all forces involved and where losses were at a minimum. Regards Art |
Computer model experiment
On May 10, 12:35*pm, Art Unwin wrote:
.... The radiation was 35 db in a shape close to that of a sphere. (when the resistance of the aluminum dipole went to zero the radiation went to a perfect sphere) The radiation was "35 db" compared to what reference value? BTW, a single, linear radiator cannot generate a perfectly spherical radiation pattern, no matter what your model tells you. Even an "infinitesimally" short, center-fed linear dipole has a figure 8 radiation pattern with a directivity (gain) of 1.5 X, or 1.76 dBi -- see any antenna engineering textbook. RF |
Computer model experiment
On May 10, 1:05*pm, Richard Fry wrote:
On May 10, 12:35*pm, Art Unwin wrote: * .... The radiation was 35 db in a shape close to that of a sphere. (when the resistance of the aluminum dipole went to zero the radiation went to a perfect sphere) The radiation was "35 db" compared to what reference value? BTW, a single, linear radiator cannot generate a perfectly spherical radiation pattern, no matter what your model tells you. Even an "infinitesimally" short, center-fed linear dipole has a figure 8 radiation pattern with a directivity (gain) of 1.5 X, or 1.76 dBi -- see any antenna engineering textbook. RF I believe the computer programs to be more up to date than the books! There certainly have been more advances since they have come into being. The programs reflect Maxwells equations which support the presence of particles which is what provide the radiation resistance and not the dipole itself. The dipole will show a donut pattern that will gradually deform to a perfect sphere when resistance drops to zero as per Poynting. I would also point out that the programs support the presence of Gaussian static particles as does mathematics. I would imagine that no matter what programs you decide to use you will get the same results as you increase the element diameter until the impedance is zero.No point in trashing computer programs in advance because of personal intuition. All I have done is removing resistance losses that do not contribute to radiation. |
Computer model experiment
On May 10, 12:35*pm, Art Unwin wrote:
I just completed a experiment with my antenna optimizer program where I had a dipole in free space and where I increased the diameter until it was close to.003 ohms resistive What this means is the current flow is right at the surface where there is no skin depth penetration involved and thus close to zero material resistance. This means that the total resistance is the radiation resistance of the surface encapsulating particles. The radiation was 35 db in a shape close to that of a sphere. (when the resistance of the aluminum dipole went to zero the radiation went to a perfect sphere) Efficiency was stated at 100% efficient pointing to 100% accountability for all forces involved and where losses were at a minimum. Regards Art Where is Lurch when I need him.... Grrrrrrrrrrrrrrrr... Once again , delusions of grandeur induced by misuse of antenna modeling programs. :/ |
Computer model experiment
On May 10, 6:49*pm, Art Unwin wrote:
On May 10, 1:05*pm, Richard Fry wrote: On May 10, 12:35*pm, Art Unwin wrote: * .... The radiation was 35 db in a shape close to that of a sphere. (when the resistance of the aluminum dipole went to zero the radiation went to a perfect sphere) The radiation was "35 db" compared to what reference value? BTW, a single, linear radiator cannot generate a perfectly spherical radiation pattern, no matter what your model tells you. Even an "infinitesimally" short, center-fed linear dipole has a figure 8 radiation pattern with a directivity (gain) of 1.5 X, or 1.76 dBi -- see any antenna engineering textbook. RF I believe the computer programs to be more up to date than the books! There certainly have been more advances since they have come into being. The programs reflect Maxwells equations which support the presence of particles which is what provide the radiation resistance and not the dipole itself. The dipole will show a donut pattern that will gradually deform to a perfect sphere when resistance drops to zero as per Poynting. I would also point out that the programs support the presence of Gaussian static particles as does mathematics. I would imagine that no matter what programs you decide to use you will get the same results as you increase the element diameter until the impedance is zero.No point in trashing computer programs in advance because of personal intuition. All I have done is removing resistance losses that do not contribute to radiation. the programs are based on the books... but even worse, they are digital approximations of the continuous formulas and as such are not completely accurate. this is especially true when extremely large or small numbers are used or there are a large number of additions done, as is common in antenna modeling programs. there are also assumptions made in the development of most of those programs that are often not stated to, or not understood by, the user, such as you. so when you set something to optimize forever or start making elements extremely skinny, fat, short, or long, or too close together, you are most likely going to get wrong, or physically unrealizable results. |
Computer model experiment
On May 10, 5:26*pm, K1TTT wrote:
On May 10, 6:49*pm, Art Unwin wrote: On May 10, 1:05*pm, Richard Fry wrote: On May 10, 12:35*pm, Art Unwin wrote: * .... The radiation was 35 db in a shape close to that of a sphere. (when the resistance of the aluminum dipole went to zero the radiation went to a perfect sphere) The radiation was "35 db" compared to what reference value? BTW, a single, linear radiator cannot generate a perfectly spherical radiation pattern, no matter what your model tells you. Even an "infinitesimally" short, center-fed linear dipole has a figure 8 radiation pattern with a directivity (gain) of 1.5 X, or 1.76 dBi -- see any antenna engineering textbook. RF I believe the computer programs to be more up to date than the books! There certainly have been more advances since they have come into being. The programs reflect Maxwells equations which support the presence of particles which is what provide the radiation resistance and not the dipole itself. The dipole will show a donut pattern that will gradually deform to a perfect sphere when resistance drops to zero as per Poynting. I would also point out that the programs support the presence of Gaussian static particles as does mathematics. I would imagine that no matter what programs you decide to use you will get the same results as you increase the element diameter until the impedance is zero.No point in trashing computer programs in advance because of personal intuition. All I have done is removing resistance losses that do not contribute to radiation. the programs are based on the books... but even worse, they are digital approximations of the continuous formulas and as such are not completely accurate. *this is especially true when extremely large or small numbers are used or there are a large number of additions done, as is common in antenna modeling programs. *there are also assumptions made in the development of most of those programs that are often not stated to, or not understood by, the user, such as you. *so when you set something to optimize forever or start making elements extremely skinny, fat, short, or long, or too close together, you are most likely going to get wrong, or physically unrealizable results. Obviously you are very experienced in generating and bug catching in antenna programs having large experiences of finding antenna errors. What exactly in the nature of antenna computer programs, which have been around for some time now, have you found them to be suspect ? In my case the program verified what mathematics show as the presence of particles on the surface and where the total input forces were used for particle propagation. Now I am aware you have taken the position that particles are not involved in radiation and thus you will resist what computer programs arrive at relying on your intuition at all times which requires no personal experience on the subject However, I am taking the program that I purchased on trust especially when it follows the maxwell equations and where I am not adverse to change. I look forward to specific examples that buttress your thoughts in a scientific manner so I may decide what to do with my program purchase. May I recommend you do the same thing with the program of your choice where you can specifically point to the areas of error where they do not meet your expectations. Why not do the same with EZNEC so Roy can learn from your personal experiences and intuitions and institute the appropriate corrections. Never mind the length of the dipole just make the diameter very very fat and see what EZNEC does. |
Computer model experiment
On May 10, 7:04*pm, Art Unwin wrote:
On May 10, 5:26*pm, K1TTT wrote: On May 10, 6:49*pm, Art Unwin wrote: On May 10, 1:05*pm, Richard Fry wrote: On May 10, 12:35*pm, Art Unwin wrote: * .... The radiation was 35 db in a shape close to that of a sphere. (when the resistance of the aluminum dipole went to zero the radiation went to a perfect sphere) The radiation was "35 db" compared to what reference value? BTW, a single, linear radiator cannot generate a perfectly spherical radiation pattern, no matter what your model tells you. Even an "infinitesimally" short, center-fed linear dipole has a figure 8 radiation pattern with a directivity (gain) of 1.5 X, or 1.76 dBi -- see any antenna engineering textbook. RF I believe the computer programs to be more up to date than the books! There certainly have been more advances since they have come into being. The programs reflect Maxwells equations which support the presence of particles which is what provide the radiation resistance and not the dipole itself. The dipole will show a donut pattern that will gradually deform to a perfect sphere when resistance drops to zero as per Poynting. I would also point out that the programs support the presence of Gaussian static particles as does mathematics. I would imagine that no matter what programs you decide to use you will get the same results as you increase the element diameter until the impedance is zero.No point in trashing computer programs in advance because of personal intuition. All I have done is removing resistance losses that do not contribute to radiation. the programs are based on the books... but even worse, they are digital approximations of the continuous formulas and as such are not completely accurate. *this is especially true when extremely large or small numbers are used or there are a large number of additions done, as is common in antenna modeling programs. *there are also assumptions made in the development of most of those programs that are often not stated to, or not understood by, the user, such as you. *so when you set something to optimize forever or start making elements extremely skinny, fat, short, or long, or too close together, you are most likely going to get wrong, or physically unrealizable results. Obviously you are very experienced in generating and bug catching in antenna programs having large experiences of finding antenna errors. What exactly in the nature of antenna computer programs, which have been around for some time now, have you found them to be suspect ? In my case the program verified what mathematics show as the presence of particles on the surface and where the total input forces were used for particle propagation. Now I am aware you have taken the position that particles are not involved in radiation and thus you will resist what computer programs arrive at relying on your intuition at all times which requires no personal experience on the subject However, I am taking the program that I purchased on trust especially when it follows the maxwell equations and where I am not adverse to change. I look forward to specific examples that buttress your thoughts in a scientific manner so I may decide what to do with my program purchase. May I recommend you do the same thing with the program of your choice where you can specifically point to the areas of error where they do not meet your expectations. Why not do the same with EZNEC so Roy can learn from your personal experiences and intuitions and institute the appropriate corrections. Never mind the length of the dipole just make the diameter very very fat and see what EZNEC does. Groan... Let me tell you the story about 24 dbi gain dipoles... Simple to model.. Then again, no, it's a futile waste of time trying to convince you of the error of your ways.. :/ Continue with fantasy hour... :/ |
Computer model experiment
On May 10, 7:10*pm, wrote:
On May 10, 7:04*pm, Art Unwin wrote: On May 10, 5:26*pm, K1TTT wrote: On May 10, 6:49*pm, Art Unwin wrote: On May 10, 1:05*pm, Richard Fry wrote: On May 10, 12:35*pm, Art Unwin wrote: * .... The radiation was 35 db in a shape close to that of a sphere. (when the resistance of the aluminum dipole went to zero the radiation went to a perfect sphere) The radiation was "35 db" compared to what reference value? BTW, a single, linear radiator cannot generate a perfectly spherical radiation pattern, no matter what your model tells you. Even an "infinitesimally" short, center-fed linear dipole has a figure 8 radiation pattern with a directivity (gain) of 1.5 X, or 1.76 dBi -- see any antenna engineering textbook. RF I believe the computer programs to be more up to date than the books! There certainly have been more advances since they have come into being. The programs reflect Maxwells equations which support the presence of particles which is what provide the radiation resistance and not the dipole itself. The dipole will show a donut pattern that will gradually deform to a perfect sphere when resistance drops to zero as per Poynting. I would also point out that the programs support the presence of Gaussian static particles as does mathematics. I would imagine that no matter what programs you decide to use you will get the same results as you increase the element diameter until the impedance is zero.No point in trashing computer programs in advance because of personal intuition. All I have done is removing resistance losses that do not contribute to radiation. the programs are based on the books... but even worse, they are digital approximations of the continuous formulas and as such are not completely accurate. *this is especially true when extremely large or small numbers are used or there are a large number of additions done, as is common in antenna modeling programs. *there are also assumptions made in the development of most of those programs that are often not stated to, or not understood by, the user, such as you. *so when you set something to optimize forever or start making elements extremely skinny, fat, short, or long, or too close together, you are most likely going to get wrong, or physically unrealizable results. Obviously you are very experienced in generating and bug catching in antenna programs having large experiences of finding antenna errors. What exactly in the nature of antenna computer programs, which have been around for some time now, have you found them to be suspect ? In my case the program verified what mathematics show as the presence of particles on the surface and where the total input forces were used for particle propagation. Now I am aware you have taken the position that particles are not involved in radiation and thus you will resist what computer programs arrive at relying on your intuition at all times which requires no personal experience on the subject However, I am taking the program that I purchased on trust especially when it follows the maxwell equations and where I am not adverse to change. I look forward to specific examples that buttress your thoughts in a scientific manner so I may decide what to do with my program purchase. May I recommend you do the same thing with the program of your choice where you can specifically point to the areas of error where they do not meet your expectations. Why not do the same with EZNEC so Roy can learn from your personal experiences and intuitions and institute the appropriate corrections. Never mind the length of the dipole just make the diameter very very fat and see what EZNEC does. Groan... Let me tell you the story about 24 dbi gain dipoles... Simple to model.. Then again, no, it's a futile waste of time trying to convince you of the error of your ways.. * :/ Continue with fantasy hour... * :/ What ever program you use let me know the result for a fat dipole. Walk the walk ! Forget the talk! |
Computer model experiment
On 5/10/2010 12:35 PM, Art Unwin wrote:
I just completed a experiment with my antenna optimizer program where I had a dipole in free space and where I increased the diameter until it was close to.003 ohms resistive What this means is the current flow is right at the surface where there is no skin depth penetration involved and thus close to zero material resistance. This means that the total resistance is the radiation resistance of the surface encapsulating particles. The radiation was 35 db in a shape close to that of a sphere. (when the resistance of the aluminum dipole went to zero the radiation went to a perfect sphere) Efficiency was stated at 100% efficient pointing to 100% accountability for all forces involved and where losses were at a minimum. Regards Art What program would this be? I would like to try and duplicate your results, as would others here. tom K0TAR |
Computer model experiment
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Computer model experiment
On May 10, 8:21*pm, tom wrote:
On 5/10/2010 12:35 PM, Art Unwin wrote: I just completed a experiment with my antenna optimizer program where I had a dipole in free space and where I increased the diameter until it was close to.003 ohms resistive What this means is the current flow is right at the surface where there is no skin depth penetration involved and thus close to zero material resistance. This means that the total resistance is the radiation resistance of the surface encapsulating particles. The radiation was 35 db in a shape close to that of a sphere. (when the resistance of the aluminum dipole went to zero the radiation went to a perfect sphere) Efficiency was stated at 100% efficient pointing to 100% accountability for all forces involved and where losses were at a minimum. Regards Art What program would this be? *I would like to try and duplicate your results, as would others here. tom K0TAR Great, tho most people on the group have yet to learn about antenna programs preferring to procede by intuition. Choose a dipole suitable for a particular frequency in FREE SPACE. Increase diameter incrementaly in the order of 1000 inches or so. Plot radiation field Continue until impedance drops to much less than 1 ohm (I dropped to about .003 ohms) Plot radiation pattern and compare change from donut to sphere shape of pattern and compare results. What to expect. Radiation will increase as impedance decreases. Maximum radiation will occur when the dipole impedance drops to zero and the particle skin becomes the sole resistance of the composite dipole. The radiation pattern will reflect point radiation within the cosmos. Note some programs provide an impedance in negative terms. It is better that impedance stays positive to determine all trends. |
Computer model experiment
On 5/10/2010 8:44 PM, Art Unwin wrote:
On May 10, 8:21 pm, wrote: On 5/10/2010 12:35 PM, Art Unwin wrote: I just completed a experiment with my antenna optimizer program where I had a dipole in free space and where I increased the diameter until it was close to.003 ohms resistive What this means is the current flow is right at the surface where there is no skin depth penetration involved and thus close to zero material resistance. This means that the total resistance is the radiation resistance of the surface encapsulating particles. The radiation was 35 db in a shape close to that of a sphere. (when the resistance of the aluminum dipole went to zero the radiation went to a perfect sphere) Efficiency was stated at 100% efficient pointing to 100% accountability for all forces involved and where losses were at a minimum. Regards Art What program would this be? I would like to try and duplicate your results, as would others here. tom K0TAR Great, tho most people on the group have yet to learn about antenna programs preferring to procede by intuition. Choose a dipole suitable for a particular frequency in FREE SPACE. Increase diameter incrementaly in the order of 1000 inches or so. Plot radiation field Continue until impedance drops to much less than 1 ohm (I dropped to about .003 ohms) Plot radiation pattern and compare change from donut to sphere shape of pattern and compare results. What to expect. Radiation will increase as impedance decreases. Maximum radiation will occur when the dipole impedance drops to zero and the particle skin becomes the sole resistance of the composite dipole. The radiation pattern will reflect point radiation within the cosmos. Note some programs provide an impedance in negative terms. It is better that impedance stays positive to determine all trends. And the program you are using is? tom K0TAR |
Computer model experiment
"tom" wrote in message t... On 5/10/2010 3:12 PM, wrote: As Clint said in the wonderful old movie, "A man's gotta know his limits". For antenna modelers it should read, "A man's gotta know the program's limits". Of course, Art thinks things have changed and the computer modelers have a better grasp upon reality than the ones even he calls "the masters". He is an example of the blind man leading himself. tom K0TAR The computer program should know its limits. Anytine a program allows the data entered to be too large or small for the calculations, it should be flagged as being out of range. Also many computer programs will use simplified formulars that can mast the true outcome. Usually it is not very much, but as all errors start to add up the end results may be way off. I often enter data that I know will be difficult for programs to use. If the program gives an answer then I usually don't use that program expecting a exect answer. Back in the Windows 3.1 and 3.11 days the simple calculator would give wrong answers to simple problems. I think if you entered 3.11 and subtracted 3.1 from it you got the wrong answer. That program was not corrected by Microsoft. |
Computer model experiment
On 5/10/2010 9:34 PM, Ralph Mowery wrote:
The computer program should know its limits. Anytine a program allows the data entered to be too large or small for the calculations, it should be flagged as being out of range. Also many computer programs will use simplified formulars that can mast the true outcome. Usually it is not very much, but as all errors start to add up the end results may be way off. I often enter data that I know will be difficult for programs to use. If the program gives an answer then I usually don't use that program expecting a exect answer. Back in the Windows 3.1 and 3.11 days the simple calculator would give wrong answers to simple problems. I think if you entered 3.11 and subtracted 3.1 from it you got the wrong answer. That program was not corrected by Microsoft. I disagree. The program cannot "know" its limits if the problem it's modeling is complex enough. So the user must understand the program and especially the math related to what the program is modeling. Blaming the program for giving you the "wrong" answer is like blaming the tires for hitting the guard rail because you exceeded their limits. Those limits are not the same under varying conditions and must be filtered by experience and understanding. tom K0TAR |
Computer model experiment
On May 10, 9:34*pm, "Ralph Mowery" wrote:
"tom" wrote in message t... On 5/10/2010 3:12 PM, wrote: As Clint said in the wonderful old movie, "A man's gotta know his limits". For antenna modelers it should read, "A man's gotta know the program's limits". Of course, Art thinks things have changed and the computer modelers have a better grasp upon reality than the ones even he calls "the masters". He is an example of the blind man leading himself. tom K0TAR The computer program should know its limits. *Anytine a program allows the data entered to be too large or small for the calculations, it should be flagged as being out of range. *Also many computer programs will use simplified formulars that can mast the true outcome. *Usually it is not very much, but as all errors start to add up the end results may be way off. I often enter data that I know will be difficult for programs to use. *If the program gives an answer then I usually don't use that program expecting a exect answer. Back in the Windows 3.1 and 3.11 days the simple calculator would give wrong answers to simple problems. *I think if you entered 3.11 and subtracted 3.1 from it you got the wrong answer. *That program was not corrected by Microsoft. Ralph, the computer program I use is AO pro which is equipt with an optimiser and based on Maxwells equation. It is required to provide arrays where the whole is in equilibrium as is its parts where all forces are taken into account according to boundary rules. It is quite easy to confirm if the results are in equilibrium.There are many programs that arer similar only they will not crunch the numbers as an optimiser will but instead calculate only from your input but without alteration. These also are based on Maxwells equations. However hams are bound to Yagi style antenna designs which are planar and not in equilibrium. This style of program is modified to encompass its primary use. There are also programs that are specifically designed for planar arrangement only per the Yagi and are not based solely on Maxwell equations that demand equilibrium. To apply any of these programs is ok for a dipole in free space say for 14 Mhz and should give the same results. Same goes if one changes the diameter as will the radiation pattern provided. So in this particular situation it matters not what program one uses the results will be the same. To conform with Maxwells equation equilibrium is demanded ie all vectors add up to zero.Since it is based on boundary rules one can make a static field dynamic which thus includes particles where the result is applicable to Maxwells equations. Thus we have an conductive element covered or encapsulated by particles the later being dynamic.This produces two resistances, the element and the particle skin. The element resistance goes to zero as the current flow moves towards the surface thus removing skin penetration losses and where all energy input is applied to propagation where we get accountability for all forces resulting in an array or element where all is in equilibrium without being planar as one must account for the earths rotation vector as well as that for gravity otherwise equilibrium cannot be retained. Thus as the diameter of the element is increased so does the surface increase for the resting particles such that the applied energy equals the energy required to elevate and propagate the supplied particles. without penetrating the surface of the element. This way we do not get into the situation of dealing with the sharing of the total resistance and thus removing element losses that do nothing for propagation, at the same time balancing the propagation vectors upon the particles alone to the applied energy. All basic classical physics which uses only fully accepted rules of the masters without alteration of any kind as predicted by Einstein in his search for the std model. |
Computer model experiment
On 5/10/2010 10:21 PM, Art Unwin wrote:
Ralph, the computer program I use is AO pro which is equipt with an optimiser and based on Maxwells equation. It is required to provide Art I was an alpha tester on AO. Do you know what an alpha tester is? I am sure that I know much more about this program's capabilities and especially its limitations than you. And almost everything you claim about it, now that I know what you're making claims against, is either wrong or inaccurate. tom K0TAR |
Computer model experiment
On May 10, 10:40*pm, tom wrote:
And almost everything you claim about it, now that I know what you're making claims against, is either wrong or inaccurate. Here's my super-gain antenna with 24 dBi gain at a TOA of 23 degrees. http://www.w5dxp.com/SUPRGAIN.EZ -- 73, Cecil, w5dxp.com |
Computer model experiment
On May 11, 7:35*am, Cecil Moore wrote:
On May 10, 10:40*pm, tom wrote: And almost everything you claim about it, now that I know what you're making claims against, is either wrong or inaccurate. Here's my super-gain antenna with 24 dBi gain at a TOA of 23 degrees. http://www.w5dxp.com/SUPRGAIN.EZ -- 73, Cecil, w5dxp.com Shall I help you file the patent? Maybe we can split the sales 50/50 ? Chortle.. We will be rich beyond our wildest dreams. Go down in history as two of the "masters"... :/ I'll be able to finally afford the GI Joe with the Kung Fu grip after all these years. :) After all, that's what really matters. |
Computer model experiment
On May 11, 4:40*am, tom wrote:
Art I was an alpha tester on AO. *Do you know what an alpha tester is? I am sure that I know much more about this program's capabilities and especially its limitations than you. And almost everything you claim about it, now that I know what you're making claims against, is either wrong or inaccurate. tom K0TAR .. How many threads here and elsewhere are dedicated to demonstrating to Art Unwin that he is wrong. The number must be in the hundreds. What a waste. Does anyone benefit? Art will go to his grave convinced that the world is in error. Usenet allows one person to irritate hundreds (at least) of people at one time, on a regular basis. A borderline personality for sure. |
Computer model experiment
Ralph Mowery wrote:
"tom" wrote in message t... On 5/10/2010 3:12 PM, wrote: As Clint said in the wonderful old movie, "A man's gotta know his limits". For antenna modelers it should read, "A man's gotta know the program's limits". Of course, Art thinks things have changed and the computer modelers have a better grasp upon reality than the ones even he calls "the masters". He is an example of the blind man leading himself. tom K0TAR The computer program should know its limits. yes and no. For EM modeling codes originally intended for use by sophisticated users with a knowledge of the limitations of numerical analysis, they might assume the user knows enough to formulate models that are "well conditioned", or how to experiment to determine this. NEC is the leading example here. It doesn't do much checking of the inputs, and assumes you know what you are doing. There were modeling articles in ARRL pubs 20 years ago that described one way to do this at a simple level: changing the number of segments in the model and seeing if the results change. The "average gain test" is another way. In many cases, the constraints on the model are not simply representable (a lot of "it depends"), so that raises an issue for a "design rule checker" that is reasonably robust. Some products that use NEC as the backend put a checker on the front (4nec2, for instance, warns you about length/diameter ratios, almost intersections, and the like) It's sort of like power tools vs hand tools. The assumption is that the user of the power tool knows how to use it. Anytine a program allows the data entered to be too large or small for the calculations, it should be flagged as being out of range. Also many computer programs will use simplified formulars that can mast the true outcome. Usually it is not very much, but as all errors start to add up the end results may be way off. There's whole books written on this for NEC. Part I of the NEC documents, in particular, discusses this. There's also a huge professional literature on various FEM computational techniques and their limitations. NEC, like most numerical codes (for mechanics, thermal, as well as EM), is very much a chainsaw without safety guards. It's up to the user to wear gloves and goggles and not cut their leg off. |
Computer model experiment
What ever program you use let me know the result for a fat dipole.
Walk the walk ! Forget the talk! Are you sure you have not violated the segment length/wire diameter ratio? From Cebik; Intermediate Antenna Modeling: "In NEC-2 it is especially important to keep the segment length (greater than) about 4 times the wire diameter. You may reduce this value by half by invoking the EK command." Also, what does your "Average Gain Test" report show? 73, Frank |
Computer model experiment
Increase diameter incrementaly in the order of 1000
inches or so. As stated earlier the above is a gross violation of the segment length/diameter ratio. Again; what does your "Average Gain Test" report say under these conditions? Frank |
Computer model experiment
On May 11, 1:38*pm, Jim Lux wrote:
Ralph Mowery wrote: "tom" wrote in message et... On 5/10/2010 3:12 PM, wrote: As Clint said in the wonderful old movie, "A man's gotta know his limits". For antenna modelers it should read, "A man's gotta know the program's limits". Of course, Art thinks things have changed and the computer modelers have a better grasp upon reality than the ones even he calls "the masters". He is an example of the blind man leading himself. tom K0TAR The computer program should know its limits. yes and no. *For EM modeling codes originally intended for use by sophisticated users with a knowledge of the limitations of numerical analysis, they might assume the user knows enough to formulate models that are "well conditioned", or how to experiment to determine this. NEC is the leading example here. It doesn't do much checking of the inputs, and assumes *you know what you are doing. There were modeling articles in ARRL pubs 20 years ago that described one way to do this at a simple level: changing the number of segments in the model and seeing if the results change. *The "average gain test" is another way. In many cases, the constraints on the model are not simply representable (a lot of "it depends"), so that raises an issue for a "design rule checker" that is reasonably robust. *Some products that use NEC as the backend put a checker on the front (4nec2, for instance, warns you about length/diameter ratios, almost intersections, and the like) It's sort of like power tools vs hand tools. *The assumption is that the user of the power tool knows how to use it. * Anytine a program allows the data entered to be too large or small for the calculations, it should be flagged as being out of range. *Also many computer programs will use simplified formulars that can mast the true outcome. *Usually it is not very much, but as all errors start to add up the end results may be way off. There's whole books written on this for NEC. *Part I of the NEC documents, in particular, discusses this. *There's also a huge professional literature on various FEM computational techniques and their limitations. *NEC, like most numerical codes (for mechanics, thermal, as well as EM), is very much a chainsaw without safety guards. * It's up to the user to wear gloves and goggles and not cut their leg off. Jim Lux of NASA no less! All of the programs clearly state that they are based on Maxwells equations. The bottom line of that equation is that for accountability for all forces involved are required and where the summation of all equals zero. This is nothing new and has been followed thru for centuries. The equations requires first and formost equilibrium and what the program supplies is easily checked that it meets these requirements. It is very simple. Showing that the solution is that inside an arbitrary boundary all within as with the whole must be resonant and in equilibrium.It requires no more than that to show if the program has achieved its object. I understand your preachings but you presented no point that can be discussed. Now you will respond that I must do such and such to back the statement above despite that those requirements are the basis of physics. So to you I will supply the same that I have supplied to others which they reject, no one has stated why. A arbitrary gaussian border containing static particles ( not waves as many summize. Gauss was very clear about the presence of static particles) in equilibrium may be made dynamic by the addition of a time varying field such that Maxell's equations can be applied to solve.I have stated the over checks that can be applied to provide correctness of this procedure. You may, of course, join the poll that swells on behalf of NASA in opposition to the above but it would provide me a great deal of delight if you provided more than to just say "I am wrong". Nobody as yet provided one mathematical reason that disputes the above, so in the absence of such you will not be alone, only your credibility suffers but you will remain in the majority of the poll in the eyes of the ham radio World. Regards Art Unwin |
Computer model experiment
Art Unwin wrote:
On May 11, 1:38 pm, Jim Lux wrote: The computer program should know its limits. yes and no. For EM modeling codes originally intended for use by sophisticated users with a knowledge of the limitations of numerical analysis, they might assume the user knows enough to formulate models that are "well conditioned", or how to experiment to determine this. NEC is the leading example here. It doesn't do much checking of the inputs, and assumes you know what you are doing. Jim Lux of NASA no less! Speaking, however, as Jim Lux, engineer, not necessarily on NASA's behalf. All of the programs clearly state that they are based on Maxwells equations. snip I understand your preachings but you presented no point that can be discussed. While NEC and its ilk are clearly based on Maxwell's equations, one should realize that they do not provide an analytical closed form solution, but, rather, are numerical approximations, and are subject to all the limitations inherent in that. They solve for the currents by the method of moments, which is but one way to find a solution, and one that happens to work quite well with things made of wires. Within the limits of computational precision, for simple cases, where analytical solutions are known to exist, the results of NEC and the analytical solution are identical. That's what validation of the code is all about. Further, where there is no analytical solution available, measured data on an actual antenna matches that predicted by the model, within experimental uncertainty. In both of the above situations, the validation has been done many times, by many people, other than the original authors of the software, so NEC fits in the category of "high quality validated modeling tools". This does not mean, however, that just because NEC is based on Maxwell's equations that you can take anything that is solvable with Maxwell and it will be equally solvable in NEC. I suspect that one could take the NEC algorithms, and implement a modeling code for, say, a dipole, using an arbitrary precision math package and get results that are accurate to any desired degree. This would be a lot of work. It's unclear that this would be useful, except perhaps as an extraordinary proof for an extraordinary claim (e.g. a magic antenna that "can't be modeled in NEC"). However, once you've done all that software development, you'd need independent verification that you correctly implemented it. This is where a lot of the newer modeling codes come from (e.g. FDTD): they are designed to model things that a method of moments code can't do effectively. |
Computer model experiment
On May 11, 4:02*pm, Jim Lux wrote:
Art Unwin wrote: On May 11, 1:38 pm, Jim Lux wrote: The computer program should know its limits. yes and no. *For EM modeling codes originally intended for use by sophisticated users with a knowledge of the limitations of numerical analysis, they might assume the user knows enough to formulate models that are "well conditioned", or how to experiment to determine this. NEC is the leading example here. It doesn't do much checking of the inputs, and assumes *you know what you are doing. Jim Lux of NASA no less! Speaking, however, as Jim Lux, engineer, not necessarily on NASA's behalf.. All of the programs clearly state that they are based on Maxwells equations. snip I understand your preachings but you presented no point that can be discussed. While NEC and its ilk are clearly based on Maxwell's equations, one should realize that they do not provide an analytical closed form solution, but, rather, are numerical approximations, and are subject to all the limitations inherent in that. *They solve for the currents by the method of moments, which is but one way to find a solution, and one that happens to work quite well with things made of wires. Within the limits of computational precision, for simple cases, where analytical solutions are known to exist, the results of NEC and the analytical solution are identical. *That's what validation of the code is all about. Further, where there is no analytical solution available, measured data on an actual antenna matches that predicted by the model, within experimental uncertainty. In both of the above situations, the validation has been done many times, by many people, other than the original authors of the software, so NEC fits in the category of "high quality validated modeling tools". This does not mean, however, that just because NEC is based on Maxwell's equations that you can take anything that is solvable with Maxwell and it will be equally solvable in NEC. I suspect that one could take the NEC algorithms, and implement a modeling code for, say, a dipole, using an arbitrary precision math package and get results that are accurate to any desired degree. *This would be a lot of work. It's unclear that this would be useful, except perhaps as an extraordinary proof for an extraordinary claim (e.g. a magic antenna that "can't be modeled in NEC"). *However, once you've done all that software development, you'd need independent verification that you correctly implemented it. This is where a lot of the newer modeling codes come from (e.g. FDTD): they are designed to model things that a method of moments code can't do effectively. Again you preach but obviously you are not qualified to address the issue. Maxwells equations are such that all forces are accounted for when the array is in a state of equilibrium. To use such an equation for an array that is not in equilibrium requires additional input ( proximetry equations) which is where error creep in.When an array is in equilibrium then Maxwell's equations are exact. The proof of the pudding is that the resulting array is in equilibrium as is its parts. AO pro by Beasley consistently produces an array in equilibrium when the optimizer is used as well as including the presence of particles dictated by Gauss., The program is of Minninec foundation which obviously does not require the patch work aproach that NEC has. On top of all that. it sees an element as one in encapsulation as forseen by Gauss by removing the resistance of the element, which produces a loss, and thus allows dealing only with all vectors as they deal with propagation. It is only because hams use Maxwell's equation for occasions that equilibrium does not exist, such as the yagi, do errors start to creep in. Any array produced solely by the use of Maxwell's equations provides proof of association by producing an array in equilibrium which can be seen as an over check.Like you, I speak only as an engineer on behalf of myself. Clearly, Maxwell had taken advantage of the presence of particles when he added displacement current so that the principle of equilibrium would be adhered to. This being exactly the same that Faraday did when explaining the transference from a particle to a time varying current when describing the workings of the cage. Regards Art |
Computer model experiment
On 5/11/2010 7:35 AM, Cecil Moore wrote:
On May 10, 10:40 pm, wrote: And almost everything you claim about it, now that I know what you're making claims against, is either wrong or inaccurate. Here's my super-gain antenna with 24 dBi gain at a TOA of 23 degrees. http://www.w5dxp.com/SUPRGAIN.EZ -- 73, Cecil, w5dxp.com I don't know what the problem is, Cecil, it looks perfectly normal to me. And it's great, effectively an omnidirectional super yagi on 40m kind of thing. You patented it, right? tom K0TAR |
Computer model experiment
On 5/10/2010 10:40 PM, tom wrote:
On 5/10/2010 10:21 PM, Art Unwin wrote: Ralph, the computer program I use is AO pro which is equipt with an optimiser and based on Maxwells equation. It is required to provide Art I was an alpha tester on AO. Do you know what an alpha tester is? I am sure that I know much more about this program's capabilities and especially its limitations than you. And almost everything you claim about it, now that I know what you're making claims against, is either wrong or inaccurate. tom K0TAR Art? No comment? tom K0TAR |
Computer model experiment
As given, the average gain is about 16.7 dB - so one knows that
something-is-afoot . . . The driven element (wire 1) is essentially touching wire 4. Current in wire 4 is unbelievably high. With use of #30 wire things improve, but wires are too close. Thanks for the example. Will use it when next talking about NEC as an example of what not to do. 73, Mac N8TT -- J. McLaughlin; Michigan, USA Home: "Cecil Moore" wrote in message ... snip Here's my super-gain antenna with 24 dBi gain at a TOA of 23 degrees. http://www.w5dxp.com/SUPRGAIN.EZ -- 73, Cecil, w5dxp.com |
Computer model experiment
On May 11, 8:30*pm, Art Unwin wrote:
When an array is in equilibrium then Maxwell's equations are exact. maxwell's equations are ALWAYS exact, it is digital models that are inexact and have limitations due to the approximations made and the numeric representations used. |
Computer model experiment
Art Unwin wrote:
On May 11, 4:02 pm, Jim Lux wrote: Again you preach but obviously you are not qualified to address the issue. Opinions on qualification differ. AO pro by Beasley consistently produces an array in equilibrium when the optimizer is used as well as including the presence of particles dictated by Gauss., The program is of Minninec foundation which obviously does not require the patch work aproach that NEC has. Interestingly, MININEC uses the very same method of moments that NEC does, but, because it's "mini" it has substantial limitations. It was developed to fit in small microcomputers of the day. I'd hardly call NEC "patchwork". The two programs do use different formulations for the basis function defining the current on the segment. There are several papers out there that compare the mechanism of MININEC vs NEC. One might start with the report by Burke and Poggio (for NEC) and the report by Julian, Logam, and Rockway (which talks about MININEC). John Rockway published a paper in 1995 describing the history and differences. "Advances in MININEC" John Rockway, James Logan IEEE Antennas and Propagation Magazine, v37, #4, August 1995, p7-12 |
Computer model experiment
On May 12, 12:42*pm, Jim Lux wrote:
Art Unwin wrote: On May 11, 4:02 pm, Jim Lux wrote: Again you preach but obviously you are not qualified to address the issue. Opinions on qualification differ. *AO pro by Beasley consistently produces an array in equilibrium when the optimizer is used as well as including the presence of particles dictated by Gauss., The program is of Minninec foundation which obviously does not require the patch work aproach that NEC has. Interestingly, MININEC uses the very same method of moments that NEC does, but, because it's "mini" it has substantial limitations. It was developed to fit in small microcomputers of the day. *I'd hardly call NEC "patchwork". The two programs do use different formulations for the basis function defining the current on the segment. There are several papers out there that compare the mechanism of MININEC vs NEC. One might start with the report by Burke and Poggio (for NEC) and the report by Julian, Logam, and Rockway (which talks about MININEC). John Rockway published a paper in 1995 describing the history and differences. "Advances in MININEC" John Rockway, James Logan IEEE Antennas and Propagation Magazine, v37, #4, August 1995, p7-12 I personaly am extremely happy with AO since I am able always to do an overcheck with respect the element resonance. I wouldn't be surprised if the next generation moved away from the present algerithms and rely purely on number crunching to obtain systems in equilibrium. I personaly believe that the programs would be much more accurate if they had a better understanding of close elements because of proximetry effects. But as long as the industry strays away from non planar forms we will have to live with close approximations. Tho using Maxwell to its limits I have yet to find a way to concentrate radiation for gain as opposed to efficiency by the introduction of other elements but I enjoy trying different methods and there is always a new vista that appears with its use. My next aproach will be a multiplicity of cells or boundaries dependent on how far my program can spread. One thing I am absolutely sure now is that particles are the staple of propagation where the neutrino act as the carrier and can well be the singular particle that Einstein envisaged based on the Earths two vectors.I was absolutely over joyed when AO allowed the radiating elements to gyrate towards zero resistance so that the encapsulating cylinder could be divorced from element thus removing losses. I see no better proof of my aproach in making Gaussian static fields dynamic which clearly exposes the presence of encapsulation that is substantiated by the math and allows propagation to be viewed as a point source. Next time one visits the moon they can apply a time varying current to the space suit to prevent the carrage of particles to the inside of the ship. Regards Art.Unwin |
Computer model experiment
On May 12, 12:10*pm, K1TTT wrote:
On May 11, 8:30*pm, Art Unwin wrote: When an array is in equilibrium then Maxwell's equations are exact. maxwell's equations are ALWAYS exact, it is digital models that are inexact and have limitations due to the approximations made and the numeric representations used. On this I have total agreement. The moment one strays from the concept of equilibrium is when we expose ourselves to errors. Regards Art |
Computer model experiment
On May 10, 7:45*pm, tom wrote:
On 5/10/2010 9:34 PM, Ralph Mowery wrote: The computer program should know its limits. *Anytine a program allows the data entered to be too large or small for the calculations, it should be flagged as being out of range. *Also many computer programs will use simplified formulars that can mast the true outcome. *Usually it is not very much, but as all errors start to add up the end results may be way off. I often enter data that I know will be difficult for programs to use. *If the program gives an answer then I usually don't use that program expecting a exect answer. Back in the Windows 3.1 and 3.11 days the simple calculator would give wrong answers to simple problems. *I think if you entered 3.11 and subtracted 3.1 from it you got the wrong answer. *That program was not corrected by Microsoft. I disagree. *The program cannot "know" its limits if the problem it's modeling is complex enough. *So the user must understand the program and especially the math related to what the program is modeling. Blaming the program for giving you the "wrong" answer is like blaming the tires for hitting the guard rail because you exceeded their limits. * Those limits are not the same under varying conditions and must be filtered by experience and understanding. tom K0TAR I've found it in my best interest to check the consistency of results in various ways, whenever I can. Often there's more than one way to think about a problem, and if the answers I get differ, I want to know why. Until I can resolve the differences, I distrust both (or all...) answers. I also like to have an idea about the tolerance on the answers, and many programs (and formulas you use to calculate answers for yourself) don't give much of a clue about the tolerance. Some are "exact," and some should be considered only approximations, but often they don't bother to tell you which. One example is formulas for calculating the impedance of TEM transmission lines; it's common to see, for air-dielectric two-wire line, Z0=276*log10(2D/d), but this is an approximation whose error becomes significant as d approaches D. Even the better formula, Z0=120invcosh(D/d), is not exact: the 120 isn't exactly correct, there's no consideration of finite conductor resistance (and resulting skin depth), and there's no consideration of the atmospheric pressure and relative humidity... I mostly agree with Tom: don't expect the program, or formula, to know how you are going to misapply it. Try to be aware of what the answers you get imply. Learn the limits of your tools (programs; formulas), and apply them wisely so they will serve you well. Do I get stung by my own foolishness in not paying proper attention to things like this? You bet I do! Just last night, I entered a coil into the Hamwaves inductance calculator and it was happy to give me an answer. The coil? Ten turns of 1mm wire in a coil 10mm diameter and 10mm long... Duh, that's a 1mm winding pitch and the turns will short together. I didn't think to check that at first. The calculator complains and won't give you an answer if the pitch is less than the wire diameter, but not if it's just equal. Considering the same very useful inductance calculator, I've learned to ignore the answer for the effective shunt stray capacitance: it in general doesn't come close to matching the value calculated from the self-resonance and the inductance. To see what I mean, try entering D=10mm, N=10, len.=20mm, d=1mm, and check what C(L,p) is reported. Now try changing D in 1mm increments up and down. OK, so I don't trust the reported C(L,p) value, but because I've checked several cases of all the other reported values against measurements of actual coils and against one or two other programs I use, I've learned to trust those other reported values, within some tolerance (that's a lot looser than the reported precision in the calculator!). -- I don't mean to pick on that inductance calculator, just to use it to illustrate what applies to pretty much all calculation programs and formulas. Cheers, Tom |
Computer model experiment
On May 12, 12:58*pm, K7ITM wrote:
.... To see what I mean, try entering D=10mm, N=10, len.=20mm, d=1mm, and check what C(L,p) is reported. *Now try changing D in 1mm increments up and down. *OK, so I don't trust the reported C(L,p) value, ... OK, it also helps to RTFM. The text down below the inductance calculator explains about this some. Also, I should have said that you need to set the "design frequency" to something low (e.g. 10MHz) to see the effect. However, the text suggests that C(L,p) value would be larger than expected...and I've also seen it for some coils to be considerably smaller. So I end up, then, not finding the lumped model including C(L,p) being very useful for the things I do, where I want a model that gives me _decent_ agreement over a broader frequency range, rather than perhaps more exact agreement over a very limited frequency range (as happens when the reported value of C(L,p) gets very large; try "design frequency" = 1MHz for that coil). Cheers, Tom |
Computer model experiment
On May 12, 3:16*pm, K7ITM wrote:
On May 12, 12:58*pm, K7ITM wrote: ... To see what I mean, try entering D=10mm, N=10, len.=20mm, d=1mm, and check what C(L,p) is reported. *Now try changing D in 1mm increments up and down. *OK, so I don't trust the reported C(L,p) value, ... OK, it also helps to RTFM. *The text down below the inductance calculator explains about this some. *Also, I should have said that you need to set the "design frequency" to something low (e.g. 10MHz) to see the effect. *However, the text suggests that C(L,p) value would be larger than expected...and I've also seen it for some coils to be considerably smaller. *So I end up, then, not finding the lumped model including C(L,p) being very useful for the things I do, where I want a model that gives me _decent_ agreement over a broader frequency range, rather than perhaps more exact agreement over a very limited frequency range (as happens when the reported value of C(L,p) gets very large; try "design frequency" = 1MHz for that coil). Cheers, Tom Remember, I have always specified that one does not go beyond the units supplied by Maxwell, Maxwell did not use lumped loads. It is stipulated that equilibrium is paramount as soon as you see the "=" sign. Thus I can say I am persueing exactnes or accuracy and not fudging.It was when Maxwell followed the edict of the "equal" sign that he was forced to add the particle elevation vector by the addition of displacement current even tho he could not describe the addition. To him it was a mathematical equation and nothing else and without explanation of the process. Art |
Computer model experiment
On May 12, 3:29*pm, Art Unwin wrote:
On May 12, 12:10*pm, K1TTT wrote: On May 11, 8:30*pm, Art Unwin wrote: When an array is in equilibrium then Maxwell's equations are exact. maxwell's equations are ALWAYS exact, it is digital models that are inexact and have limitations due to the approximations made and the numeric representations used. On this I have total agreement. The moment one strays from the concept of equilibrium is when we expose ourselves to errors. Regards Art ok, so you DO agree that maxwell's equations that make no mention of particles like neutrinos, gravity, coriolis forces, or levitation ARE correct! And therefor you must agree that the representation of gauss's law encapsulated in maxwell's equations, WITHOUT an explicit t in it must be correct! You must also be admitting that your optimization experiments are full of errors. wow, now its time to go and rejoice, art has finally come around to the real world! |
Computer model experiment
On May 12, 3:16*pm, K7ITM wrote:
On May 12, 12:58*pm, K7ITM wrote: ... To see what I mean, try entering D=10mm, N=10, len.=20mm, d=1mm, and check what C(L,p) is reported. *Now try changing D in 1mm increments up and down. *OK, so I don't trust the reported C(L,p) value, ... OK, it also helps to RTFM. *The text down below the inductance calculator explains about this some. *Also, I should have said that you need to set the "design frequency" to something low (e.g. 10MHz) to see the effect. *However, the text suggests that C(L,p) value would be larger than expected...and I've also seen it for some coils to be considerably smaller. *So I end up, then, not finding the lumped model including C(L,p) being very useful for the things I do, where I want a model that gives me _decent_ agreement over a broader frequency range, rather than perhaps more exact agreement over a very limited frequency range (as happens when the reported value of C(L,p) gets very large; try "design frequency" = 1MHz for that coil). Cheers, Tom Again I state. If you are using Maxwell equations you cannot stray from the units supplied.Hams do not follow the rules with respect to antennas so approximations are literally garranteed. Using Maxwells equations alone you have the presence of point radiation. With a single point radiation the rules of physics state that radiation limits is in the form of a sphere. If one states you cannot have a sphere of radiation they are breaking all the laws of physics and I certainly had no part in the making of the rules. Regards Art |
Computer model experiment
On May 12, 4:49*pm, Art Unwin wrote:
On May 12, 3:16*pm, K7ITM wrote: On May 12, 12:58*pm, K7ITM wrote: ... To see what I mean, try entering D=10mm, N=10, len.=20mm, d=1mm, and check what C(L,p) is reported. *Now try changing D in 1mm increments up and down. *OK, so I don't trust the reported C(L,p) value, ... OK, it also helps to RTFM. *The text down below the inductance calculator explains about this some. *Also, I should have said that you need to set the "design frequency" to something low (e.g. 10MHz) to see the effect. *However, the text suggests that C(L,p) value would be larger than expected...and I've also seen it for some coils to be considerably smaller. *So I end up, then, not finding the lumped model including C(L,p) being very useful for the things I do, where I want a model that gives me _decent_ agreement over a broader frequency range, rather than perhaps more exact agreement over a very limited frequency range (as happens when the reported value of C(L,p) gets very large; try "design frequency" = 1MHz for that coil). Cheers, Tom Again I state. *If you are using Maxwell *equations you cannot stray from the units supplied.Hams do not follow the rules with respect to antennas so approximations are literally garranteed. Using Maxwells equations alone you have the presence of point radiation. With a single point radiation the rules of physics state that radiation limits is in the form of a sphere. If one states you cannot have a sphere of radiation they are breaking all the laws of physics and I certainly had no part in the making of the rules. Regards Art- Hide quoted text - - Show quoted text - you can have a spherically symetric static electric field as is easily shown by gauss's law. but in order to have 'radiation' (implying em wave propagating through space) you must have movement of some kind, that immediately removes the spherical symetry by creating an axis defined by the direction of movement. this is why even the theoretical infinitesimal dipole still produces a doughnut shaped field in free space. |
Computer model experiment
On May 12, 3:49*pm, Art Unwin wrote:
Again I state. *If you are using Maxwell *equations you cannot stray from the units supplied.Hams do not follow the rules with respect to antennas so approximations are literally garranteed. Maybe this is good.. I have noticed my antennas tend to actually work as radiators of RF, where as most of yours seem to prefer to turn it to heat. :/ I think Maxwell must be taking you for a big ride. I bet he's up there is the land of the big RF just laughing his head off at all this silly jibber jabber you keep blaming him for. Using Maxwells equations alone you have the presence of point radiation. With a single point radiation the rules of physics state that radiation limits is in the form of a sphere. If one states you cannot have a sphere of radiation they are breaking all the laws of physics and I certainly had no part in the making of the rules. Regards Art How many cases of a single point of radiation have you seen in the real world, using real world antennas? This is not a trick question. |
Computer model experiment
On May 11, 9:23*pm, tom wrote:
I don't know what the problem is, Cecil, it looks perfectly normal to me. Yep, one of its claims to fame is that it passes all the geometry and segmentation checks that EZNEC runs. However, it does violate the "spacing of elements" admonition in the manual. -- 73, Cecil, w5dxp.com |
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